OBJECTIVES: To study secular trends in cardiovascular risk factors in four different cohorts of women examined in 1968-1969, 1980-1981, 1992-1993 and 2004-2005. DESIGN: Comparison of four representative cohorts of 38- and 50-year-old women over a period of 36 years. SETTING: Gothenburg, Sweden with approximately 450,000 inhabitants. SUBJECTS: Four representative samples of 38- and 50-year-old women were invited to free health examinations (participation rate 59-90%, n =1901). MAIN OUTCOME MEASURES: Body mass index (BMI), systolic and diastolic blood pressure (SBP, DBP), leisure time exercise, use of antihypertensive medication, smoking, levels of haemoglobin, b-glucose, s-cholesterol, s-triglycerides and HDL-cholesterol. RESULTS: There was no significant difference in mean BMI from 1968-1969 versus 2004-2005. Mean leisure time exercise was significantly higher in later born cohorts; in 1968, around 15% were physically active compared with 40% in 2004. SBP and DBP, mean s-cholesterol and s-triglyceride levels were significantly lower in both 38- and 50-year-old cohorts in 2004-2005 versus 1968-1969. HDL-cholesterol (not measured until 1992-1993), showed a significantly higher mean level in 2004-2005. Reduction of risk factors was apparent in women with a high as well as low level of physical activity. Smoking declined most in women with high levels of physical activity. CONCLUSIONS: Several cardiovascular risk factors related to lifestyle have improved in middle-aged women from the 1960s until today. Most of the positive trends are observed in women with both low and high physical activity.